Twitter marks Black Lives Matter movement with special emoji

The Black Lives Matter Twitter emoji is back after a spate of police-involved shootings of black men, which occurred earlier this week.

The emoji, which features three clenched fists in varying shades of brown, was brought back on Friday.

The decision to feature the emoji at the end of the hashtag "#BlackLivesMatter" was announced by Blackbirds -- an official account run by Twitter employees that aims to "celebrate and encourage diverse perspectives."

Notable activists and celebrities were among the hundreds of voices that rang out on social media, using the #BlackLivesMatter hashtag.